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Appendix E. The XHTML 1.0 DTD
Appendix E. The XHTML 1.0 DTD
The XHTML 1.0 standard is formally defined as three Extensible Markup Language (XML) Document Type Definitions (DTDs): the Strict DTD, the Transitional DTD, and the Frameset DTD. These DTDs correspond to the respective HTML 4.01 DTDs, defining the same elements and attributes using XML rather than the Standard Generalized Markup Language (SGML) as the DTD authoring language.
The Strict DTD defines only those elements that are not deprecated in the HTML 4.01 standard. Ideally, everyone would create XHTML documents that conform to the Strict DTD. The Transitional DTD includes all those deprecated elements and more accurately reflects the HTML in use today, with many older elements still in common use. The Frameset DTD is identical to the Transitional DTD, with the exception that the document <body> is replaced by the <frameset> element.
